Transcript Why does a violin sound different from a horn?

Why does a violin sound
different from a horn?
Several kinds of audible information
Pitch
Timbre
Attack
Decay
Vibrato
We need to systematically compare sounds…
Thus, we need to quantify sound
Thus, we need to measure sound
The Waveform
• Plot motion of air (pressure vs. time)
pressure
• Microphone converts pressure to voltage
time (ms)
Compare Waveforms
period
T = 2.2 ms
T = 7 ms
f = 1/T = 460 Hz
f = 1/T = 140 Hz
pure tone
sine wave
simplest sound
simplest waveform
amplitude
period
• Single period implies a single, constant frequency
• Described by only two numbers: f, A
How can we describe more complicated sounds?